Biology subjects

Schlupp, I.

Publications and source records attributed to Schlupp, I..

4 recordsLinked to original sources

bioRxiv2026

Ancestral gene flow shaped the singular origin of the Amazon molly

The evolutionary origins of asexuality remain poorly understood, despite extensive research on its ecological and evolutionary consequences. Asexuality often arises through hybridization between species with intermediate genomic divergence, implying that hybrid-induced asexuality may be partly repeatable. The Amazon molly (Poecilia formosa), the first asexual vertebrate known to science, challenges this view: repeated experimental crosses between its extant parental species have failed to recreate a stable Amazon molly-like lineage. This apparent paradox gave rise to the Rare Formation Hypothesis, which proposes that stable asexuality requires an exceptionally specific genomic combination. Here, we combine experimental crosses, molecular cytogenetics, and population genomics to test whether ancestral introgression before the hybrid speciation event set the stage for the singular origin of the Amazon molly. We show that most experimental hybrids are viable but sexual, but that a subset of F1 hybrids produce unreduced eggs through a mechanism distinct from that of the Amazon molly. Population genomic analyses reveal that introgression between parental species likely predated the formation of the Amazon molly, and shared homozygous tracts across Amazon molly genomes support inheritance from admixed progenitors. Together, our findings reconcile the repeatable and contingent views of the origin of asexuality, suggesting that ancestral introgression may be the missing mechanism assembling the rare genomic combinations required for seemingly unrepeatable evolutionary innovations, including the emergence of asexual species.

evolutionary biology↗

bioRxiv2023

Why Do Hybrids Turn Down Sex?

Asexual reproduction is ancestral in prokaryotes; the switch to sexuality in eukaryotes is one of the major transitions in the history of life. The study of the maintenance of sex in eukaryotes has raised considerable interest for decades and is still one of evolutionary biologys most prominent question. The observation that many asexual species are of hybrid origin have led some to propose that asexuality in hybrids results from sexual processes being disturbed because of incompatibilities between the two parental species genomes. This proximate theory appears difficult in real life, as it requires fundamental reproductive traits to be profoundly altered without collapsing individuals fertility. Repeated failures to produce asexual Amazon Molly in the lab through crossing experiments show that we are still in need of an evolutionary explanation. Here, we present a mathematical model and propose an adaptive route for the evolution of asexuality from previously sexual hybrids. Under smaller reproductive alterations, we show that asexuality can evolve to rescue hybrids reproduction. Importantly, we highlight that when incompatibilities only affect the fusion of sperm and eggs genomes, unreduced meiosis and paternal genome elimination can evolve separately, greatly facilitating the overall evolutionary route.

evolutionary biology↗

bioRxiv2021

Male attention allocation depends on social context

Attention, although limited, is a mechanism used to filter large amounts of information and determine what stimuli are most relevant at a particular moment. In dynamic social environments, multiple individuals may play a pivotal role in any given interaction where a males attention may be divided between a rival, a current mate, and/or future potential mates. Here, we investigated impacts of the social environment on attention allocation in male sailfin mollies, Poecilia latipinna, which are a part of a sexual-unisexual mating system with the Amazon molly, Poecilia formosa. We asked: 1) Does the species of female influence the amount of attention a male allocates to her? And 2) Is a males attention towards his mate influenced by different social partners? Males direct more attention toward a stimulus female when she was a conspecific. We also show that males perceive a larger male as a more relevant stimulus to pay attention to than a smaller male, and a conspecific female as a more relevant stimulus compared to a heterospecific female. Our results show differential allocation of attention is dependent upon multiple components of the social environment in which an individual interacts. SignificanceThis study investigates how attention is allocated in males when presented with social distractions. Assuming that attentional capacity is finite, males may face a tradeoff between different cognitive-demanding stimuli, such as rival males and potential future mates, when mating. Here, we show that male attention allocation in both intra- and intersexual interactions is multifaceted and context dependent. This suggests that individuals within the social environment vary in how meaningful (i.e., able to capture attention) they are to males during mating encounters. Understanding how social partners can cause a shift of attention away from a mating opportunity is essential to understanding the influence of the social context on sexual selection.

animal behavior and cognition↗

bioRxiv2020

Elevational gradients do not affect thermal tolerance at local scale in populations of livebearing fishes of the genus Limia (Teleostei, Poeciliidae)

One of the main assumptions of Janzens (1976) mountain passes hypothesis is that due the low overlap in temperature regimes between low and high elevations in the tropics, organisms living in high-altitude evolve narrow tolerance for colder temperatures while low-altitude species develop narrow tolerance for warmer temperatures. Some studies have questioned the generality of the assumptions and predictions of this hypothesis suggesting that other factors different to temperature gradients between low and high elevations may explain altitudinal distribution of species in the tropics. We assessed variation in tolerance to extreme temperatures (measured as critical thermal minimum (CTmin) and maximum (CTmax)) and also compared thermal breadth for populations of eight species of livebearing fishes of the genus Limia occurring in three Caribbean islands and that occupy different altitudinal distribution. Our results showed that species analyzed had significant differences in thermal limits and ranges. Generally, species distributed in high and low elevations did not differ in thermal limits and showed a wider range of thermal tolerance. However, species living in mid-elevations had narrower range of temperature tolerance. We found no significant effect of phylogeny on CTmin, CTmax and thermal ranges among species. This study did not provide evidence supporting Janzens hypothesis at a local scale since thermal tolerance and altitudinal distribution of Limia species were not related to temperature gradients expected in nature. Phylogeny also did not explain the patterns we observed. We suggest that biotic factors such as species interactions, diet specializations, and others should be taken into account when interpreting current distribution patterns of Limia species.

ecology↗